using System;
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Audio;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.GamerServices;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Input;
using Microsoft.Xna.Framework.Input.Touch;
using Microsoft.Xna.Framework.Media;

namespace ChildrenOfWar
{
    /// <summary>
    /// This is the main type for your game
    /// </summary>
    public class COWGame : Microsoft.Xna.Framework.Game
    {
        internal GraphicsDeviceManager graphics;
        internal SpriteBatch spriteBatch;
        COWLevel level;//current level

        //Touch varibles. Notes where the last screen touch was and if the screen was touched during the lasy cycle.
        Vector2 oldTouchLoc;
        bool bScreenTouched;

        // Game State variables
        #region Game States
        int GAMESTATE;
        int menuSTATE = 0;
        int playSTATE = 1;
        int creditSTATE = 2;
        #endregion

        // Splash Screen
        #region Splash Screen vars
        Texture2D texSplash;
        Vector2 posSplash;
        bool hasSplashDisplayed = false;
        #endregion

        public COWGame()
        {
            graphics = new GraphicsDeviceManager(this);
            Content.RootDirectory = "Content";

            // Frame rate is 30 fps by default for Windows Phone.
            TargetElapsedTime = TimeSpan.FromTicks(333333);

            // Extend battery life under lock.
            InactiveSleepTime = TimeSpan.FromSeconds(1);
        }

        

        /// <summary>
        /// Allows the game to perform any initialization it needs to before starting to run.
        /// This is where it can query for any required services and load any non-graphic
        /// related content.  Calling base.Initialize will enumerate through any components
        /// and initialize them as well.
        /// </summary>
        protected override void Initialize()
        {
            //test logic, immediatly loads a level upon intialization
            level = COWLevelIO.LoadLevelASCII("content\\Level1.txt");//COWLevelIO.LoadLevel("content\\level.bin");
            level.Initalize(this);

            GAMESTATE = menuSTATE;


            base.Initialize();
        }

        /// <summary>
        /// LoadContent will be called once per game and is the place to load
        /// all of your content.
        /// </summary>
        protected override void LoadContent()
        {
            // Create a new SpriteBatch, which can be used to draw textures.
            spriteBatch = new SpriteBatch(GraphicsDevice);

            texSplash = Content.Load<Texture2D>("PantherScreenSmall");
            posSplash = new Vector2(0, 0);
        }

        /// <summary>
        /// UnloadContent will be called once per game and is the place to unload
        /// all content.
        /// </summary>
        protected override void UnloadContent()
        {
        }

        /// <summary>
        /// Allows the game to run logic such as updating the world,
        /// checking for collisions, gathering input, and playing audio.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Update(GameTime gameTime)
        {
            // Allows the game to exit
            if (GamePad.GetState(PlayerIndex.One).Buttons.Back == ButtonState.Pressed)
                this.Exit();

            if (GAMESTATE == menuSTATE)
            {
                if (Mouse.GetState().LeftButton == ButtonState.Pressed)
                    GAMESTATE = playSTATE;
            }

            if (GAMESTATE == playSTATE)
            {
                //If the screen is touched, record the vector of the touch location. If it was touched during the last update (bScreenTouched is already true) 
                //then move the camera the difference between this touch and the last touch. Then update the old touch location and note that the screen was touched.
                //Otherwise, simply note that the screen was not touched.
                if (Mouse.GetState().LeftButton == ButtonState.Pressed)
                {
                    Vector2 TouchLoc = new Vector2(Mouse.GetState().X, Mouse.GetState().Y);
                    if (bScreenTouched)
                    {
                        level.MoveCamera(oldTouchLoc - TouchLoc);
                    }
                    bScreenTouched = true;
                    oldTouchLoc = TouchLoc;
                }
                else
                {
                    bScreenTouched = false;
                }
            }
            base.Update(gameTime);
        }

        /// <summary>
        /// This is called when the game should draw itself.
        /// </summary>
        /// <param name="gameTime">Provides a snapshot of timing values.</param>
        protected override void Draw(GameTime gameTime)
        {
            GraphicsDevice.Clear(Color.White);
            spriteBatch.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend, null, null, null, null, level.levelCam.getCamTrans(graphics.GraphicsDevice));

            if (GAMESTATE == menuSTATE)
            {
                
                spriteBatch.Draw(texSplash, posSplash, Color.White);
                
            }

            if (GAMESTATE == playSTATE)
            {
                //If a level exists, draw it.
                if (level != null)
                {
                    level.draw(spriteBatch);
                }
            }

            spriteBatch.End();
            base.Draw(gameTime);
        }
    }
}
